Distributed Antenna System Uplink Path Segmentation
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Solution Overview
Problem
Existing Distributed Antenna Systems for massive MIMO applications face challenges in scaling with a high number of devices and antennas, leading to increased footprint and cost, while maintaining independent uplink and downlink paths, and suffer from noise figure increases due to multiple Remote Units serving the same sector.
Innovation Solution
A new architecture that increments the number of independent uplink paths by optimizing space occupation, complexity, and cost, featuring a plurality of Point of Interface modules, optical modules, and Remote Units with band-pass filters and Low Noise Amplifiers, and eliminates internal RF combiners in optical modules to maintain signal separation until the Baseband Unit, reducing noise figure and system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple Remote Units are used to serve the same sector to increase the number of independent uplink paths, then the system capacity and positioning precision are improved, but the noise figure increases and system complexity rises
Solution Approach 1:
The optical module is designed to handle multiple functions: it performs E/O conversion for downlink signals and O/E conversion for uplink signals, and simultaneously supports multiple independent uplink paths. This multi-functionality allows the system to achieve higher capacity with fewer components, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The system segments the uplink paths by maintaining them separate through the optical module without internal RF combining. Each uplink path remains independent from the RF stage through optical conversion, allowing multiple Remote Units to serve the same sector without increasing noise figure, thus improving reliability without proportional complexity increase.
2Reliability
If the number of MIMO paths is increased to support massive MIMO applications, then the system performance is boosted, but the DAS footprint and cost rapidly rise
Solution Approach 1:
Multiple independent uplink paths from different Remote Units are merged at the optical module level through O/E conversion, rather than combining RF signals earlier in the chain. This merging approach allows multiple MIMO paths to share common infrastructure components, reducing DAS footprint while maintaining the performance benefits of multiple independent paths for massive MIMO applications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design allows for more precise positioning, reduced noise figure, and lower system costs by maintaining signal independence until the BBU, enabling more efficient use of diversity techniques and reducing the overall system footprint and complexity, while supporting higher-order MIMO systems with fewer components.
Implementation Method 1
The OTRX1 and OTRX2 (of the OTRX 1:2 type) perform the E/O conversion and convey the signal towards the first cross-polarized antenna ANT1 passing through the first and second Remote Units RU1 and RU2
Implementation Method 2
The uplinks signals run through the same path towards the BBU... doubling the whole system components described above by using: a second Point of Interface POI2, a third and fourth n-plexer3 and n-plexer4, a third and fourth optical modules OTRX3 and OTRX4
Implementation Method 3
featureing a plurality of Point of Interface modules, optical modules, and Remote Units with band-pass filters and Low Noise Amplifiers
Implementation Method 4
featureing a plurality of Point of Interface modules, optical modules, and Remote Units with band-pass filters and Low Noise Amplifiers
Data Source
AI summary
The distributed Antenna System for massive MIMO applications, comprises: a plurality of Point of Interface modules connectable to a Baseband Unit and configured for converting a digital data flow coming from the Baseband Unit to RF signals and/or for converting incoming RF signals to a digital data flow to be sent to the Baseband Unit; a plurality of optical modules operatively connected to the plurality of Point of Interface modules and configured for performing an electro-optical conversion of the RF signals; a plurality of Remote Units operatively connected to the optical modules and to a plurality of antennas; in which the optical modules comprises a plurality of uplink paths separated from each other and provided with respective uplink outputs.